The period prevalence of major depressive disorder (MDD) was 12.7% during pregnancy and a striking 14.5% women experience postpartum depression. Although MDD is prevalent, only 1 in 5 Americans receive any guideline-concordant intervention, and the rate is even lower in pregnant women than non-pregnant women. Women who become pregnant have a significantly greater drop in both outpatient therapy visits and antidepressant prescription claims compared to matched nonpregnant women, and they do not resume after birth. Psychotherapy is the preferred treatment of most women but it is not readily available in all practice settings nor is it feasible for some mothers. Many physicians avoid drug treatment of pregnant women because of lack of expertise or medicolegal liability. For most pregnant women, the reality is that accessible and acceptable mental health treatment is very limited. Low treatment rates are juxtaposed against mounting evidence that MDD increases risk to the pregnant woman and fetus. Gestational MDD is associated with lack of prenatal care, poor nutrition, smoking, alcohol and drug use and suicide. It incurs an increased risk for obesity, low-birth-weight infants and preterm delivery. Pregnant depressed women are more likely to have infants who are withdrawn and irritable, cry excessively and are difficult to console. Other serious sequelae of maternal mental illness are increased rates of accidental injury, child abuse, neglect, and infanticide. When children of depressed mothers develop depression, the onset is earlier, the course is more severe, and more medical and substance abuse problems coexist compared to offspring of non-depressed mothers. Children exposed to maternal MDD during pregnancy are four times more likely than those not exposed to be depressed at age 16 years. Therefore, intervention for psychiatric illnesses as early as possible has potential to prevent negative sequelae for parents and families. The relationship between maternal MDD and multiple childhood problems is a continuum that often begins during pregnancy. The goals of the proposed conference are: 1) increase recognition that perinatal mental illness is a very common and understudied clinical problem; 2) enhance interdisciplinary communication and research collaboration; 3) focus on optimizing treatment for pregnant women and reducing adverse outcomes for infants; and 4) provide training opportunities for new investigators.